What tool can be used to determine the probability of traits appearing in cross-bred organisms?

• A. Pedigree Charts
• B. Punnet Squares
• C. Microscope
• D. Petri Dishes

Answer: (B)

Punnett squares are a simple way to predict how likely it is that offspring will show particular traits when two organisms mate. By placing one parent’s alleles along the top and the other parent’s alleles along the side, you fill in the box for every possible combination the offspring could inherit. This shows the possible genotypes and, for traits with a straightforward dominant-recessive pattern, the likely phenotypes as well, often expressed as fractions or percentages.

For example, if both parents are heterozygous for a trait (Aa × Aa), the square shows 25% AA, 50% Aa, and 25% aa. Phenotypically, about three out of four offspring would display the dominant trait, while one would display the recessive trait. If one parent is AA and the other is aa, all offspring will be Aa and show the dominant trait.

Other tools have different uses: pedigree charts track traits across generations, a microscope helps you observe cells, and Petri dishes are used to culture microorganisms.